* Astronomy

Blobrana · L

RE: Trumpler 14

Blobrana · L

Title: Distance and the Initial Mass Function of Young Open Clusters In The Eta Carina Nebula: Tr 14 and Tr 16
Authors: Hyeonoh Hur, Hwankyung Sung, Michael S. Bessell

We present new UBVI_C CCD photometry of the young open clusters Trumpler 14 (Tr 14) and Trumpler 16 (Tr 16) in the eta Carina nebula. We also identify the optical counterpart of Chandra X-ray sources and Two Micron All Sky Survey point sources. The members of the clusters were selected from the proper motion study, spectral types, reddening characteristics, and X-ray or near-IR excess emission. An abnormal reddening law R_V,cl=4.4±0.2 was obtained for the stars in the eta Carina nebula using the 141 early-type stars with high proper motion membership probability (P_u\geq70). We determined the distance to each cluster and conclude that Tr 14 and Tr 16 have practically the same distance modulus of V_0-M_V=12.3±0.2 mag (d=2.9±0.3 kpc). The slope of the initial mass function was determined to be {\Gamma}=-1.3±0.1 for Tr 14, {\Gamma}=-1.3±0.1 for Tr 16, and {\Gamma}=-1.4±0.1 for all members in the observed region for the stars with log m\geq0.2. We also estimated the age of the clusters to be about 1 -- 3 Myr from the evolutionary stage of evolved stars and low-mass pre-main-sequence stars.

Read more (765kb, PDF)

Blobrana · L

Title: A benchmark for multi-conjugated AO: VLT-MAD observations of the young massive cluster Trumpler 14
Authors: B. Rochau, W. Brandner, A. Stolte, T. Henning, N. Da Rio, M. Gennaro, F. Hormuth, E. Marchetti, P. Amico

MAD is the first multi-conjugated adaptive optics system at the VLT. We present H and Ks observations of the young massive cluster Trumpler 14 revealing the power of MCAO systems by providing a homogeneous Strehl ratio over a large field of view. Mean Strehl ratios of 6.0 and 5.9 per cent with maximum Strehl ratios of 9.8 and 12.6 per cent in H and Ks, respectively, show significant improvement of the spatial PSF stability compared to single-conjugated adaptive optics systems. Photometry of our observations cover a dynamic range of ~10 mag including 2-3 times more sources than comparable seeing-limited observations. The colour-magnitude diagram reveals that the massive cluster originated in a recent starburst-like event 1±0.5 Myr ago. We tentatively detect hints for an older population of 3 Myr suggesting that low intensity star formation might have been going on in the HII region for a few Myr. We derive the luminosity function and mass function between 0.1 solar masses and 3.2 solar masses and identify a change of the power law slope of the mass function at m_c~0.53(+0.12/-0.10) solar masses. The MF appears shallow with power law slopes of Gamma1=-0.50±0.11 above m_c and Gamma2=0.63±0.32 below m_c.

Read more (625kb, PDF)

Blobrana · L

Stellar Family Portrait Takes Imaging Technique to New Extremes
The young star cluster Trumpler 14 is revealed in another stunning ESO image. The amount of exquisite detail seen in this portrait, which beautifully reveals the life of a large family of stars, is due to the Multi-conjugate Adaptive optics Demonstrator (MAD) on ESO's Very Large Telescope. Never before has such a large patch of sky been imaged using adaptive optics, a technique by which astronomers are able to remove most of the atmosphere's blurring effects.
Noted for harbouring Eta Carinae - one of the wildest and most massive stars in our galaxy - the impressive Carina Nebula also houses a handful of massive clusters of young stars. The youngest of these stellar families is the Trumpler 14 star cluster, which is less than one million years old - a blink of an eye in the Universe's history. This large open cluster is located some 8000 light-years away towards the constellation of Carina (the Keel).

Read more

-- Edited by Blobrana on Thursday 3rd of December 2009 03:46:21 PM